Elements are the purest, simplest substance.
Compound is a combination of two or more elements
2. Label the diagram below and define the terms that you label. Kim Le
proton: positively charged subatomic particle located in the nucleus.
neutron: uncharged subatomic particle located in the nucleus
electrons: subatomic particles that are negatively charged located in the electron cloud; mass = 1/1800 amu
3. Contrast the terms atomic number and atomic mass. Kim Le
The atomic number contains the number of protons. The number of protons is also the number of electrons. Atomic mass on the otherhand composes of the number of protons and neutrons combined.
(LINH)
Atomic number is the number of protons present in each atom of an element, which is also the same as the number of electrons if the atom is neutral.
Atomic mass is the average weight of all the element’s isotopes (atoms with the same number of protons, neutrons, but different number of electrons, hence a different atomic weight).
4. What is an isotope and what is “special” about radioactive isotopes? Isotope: an alternative form of an element with a different number of neutrons but the same number of protons. Radioactive isotopes: unstable isotopes that spontaneously emit radiation when they decay to become more stable --> typically become a different element.
5. Explain how radioactive tracers are used in science?
Radioactive tracers are actually radioactive isotopes. Radioactivity is the property possessed by some elements of spontaneously emitting energy in the form of particles or waves by disintegration of their atomic nuclei. It is the measure of the decaying of this energy. These "tracers" can be used in science to determine the age of artifacts. Through measuring what's left of the radioactivity, scientists can determine the date of fossils.
6. Explain how the electron distance from the nucleus relates to the amount of energy within that electron shell. Look at figure 9-3 for clarification.
The farther an electron's distance is from the nucleus, the more energy an atom has within its electron shell. Since they have higher energies, electrons are more able to "run off" or become farther from the nucleus.
(Mike)
More Distance = More Energy Less Distance = Less Energy
(Mike)
7. Which electrons – the most energetic electrons - determines interactions between atoms?
The valence electrons, which are the most energetic electrons, determines interactions between atoms.
8. Define the following terms: (Julie Le)
Chemical bond are atoms held together by forces of attraction.
Covalent bond involve the sharing of elections between atoms in a way that results in each atom having filling the valence electrons.
An example of covalent bond in a water molecule.
Single covalent bond is when one pair of electron is shared between two atoms.
Single Bond in a Hydrogen molecule
Double covalent bond is when two pairs of electrons are shared, which is represented by2 parallel solid lines.
Valence electrons is the electrons in the outer shell ( valence shell) of an atom.
Electronegativity is the measure of an atom';s attraction for electrons.
Nonpolar covalent bond is a chemical bond formed by the equal sharing of electrons between atoms of approximately equal electronegativity.
Polar covalent bond is a chemcial bond formed by the sharing of electrons bewteeen atoms that differ in electronegativity.
9. What is the difference between a structural and molecular formula? (Noreen Delfin)
A molecular formula shows the number of atoms in each molecule. A structural formula not only shows the amount of atoms in a molecule, but it also shows the arrangement of atoms as well.
This can be seen in the folllowing formulas for water:
The molecular formula for water is H2O.
The 2 in "H2O" refers to the number of Hydrogen atoms in one molecule of water. In this formula, oxygen has only one atom. The biggest difference between the molecular formula and the structural formula of water is the absence of the arrangement of atoms. From the formula H2O, we only know that there are two atoms of hydrogen and one atom of oxygen, but the formula does not tell us where they are located on the molecule. However, the arrangement can be seen in the structural formula. The structural formula of water:
As seen in the above picture of the structural formula, we can see where the two hydrogens and one oxygen is arranged in the molecule. Essentially, this formula provides the number of atoms along with the structure of the atoms.
In the above picture of
10. How do ionic bonds compare with covalent bonds? (Compare Figures 2-7 and 2-9)
this is a ionic bond. This occurs when one ion has more electromagnetically then the other. One ion usual gives one or more valence electron to the other which allows the other ion to finish there outter shell.
this is a covalent bond. This occurs when atoms bond together and share one more more electrons. The electrons are shared and circle between both atoms that are bonded together.
The most distinguish difference from ionic and covalent is that ionic is more of giving an electron while covalent is a sharing of an electron.
Navy Swag
11. Compare and contrast hydrogen bonds and van der Waals interactions.
This is a hydrogen bond:
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom such as fluorine, oxygen, and nitrogen that comes from another molecule or chemical group. The hydrogen must be covalently bonded to another electronegative atom to create the bond.
On the other hand, this is Van der Waals Force
is an attractive force between atoms or nonpolar molecules caused by an instantaneous dipole moment of one atom or molecule that induces a similar temporary dipole moment in adjacent atoms or molecules.
Although both are relatively weak, the hydrogen bond is stronger than Van der Waals' interactions
Elements are the purest, simplest substance.
Compound is a combination of two or more elements
2. Label the diagram below and define the terms that you label. Kim Le
proton: positively charged subatomic particle located in the nucleus.
neutron: uncharged subatomic particle located in the nucleus
electrons: subatomic particles that are negatively charged located in the electron cloud; mass = 1/1800 amu
3. Contrast the terms atomic number and atomic mass. Kim Le
The atomic number contains the number of protons. The number of protons is also the number of electrons. Atomic mass on the otherhand composes of the number of protons and neutrons combined.
(LINH)
Atomic number is the number of protons present in each atom of an element, which is also the same as the number of electrons if the atom is neutral.
Atomic mass is the average weight of all the element’s isotopes (atoms with the same number of protons, neutrons, but different number of electrons, hence a different atomic weight).
4. What is an isotope and what is “special” about radioactive isotopes?
Isotope: an alternative form of an element with a different number of neutrons but the same number of protons.
Radioactive isotopes: unstable isotopes that spontaneously emit radiation when they decay to become more stable --> typically become a different element.
5. Explain how radioactive tracers are used in science?
Radioactive tracers are actually radioactive isotopes. Radioactivity is the property possessed by some elements of spontaneously emitting energy in the form of particles or waves by disintegration of their atomic nuclei. It is the measure of the decaying of this energy. These "tracers" can be used in science to determine the age of artifacts. Through measuring what's left of the radioactivity, scientists can determine the date of fossils.
6. Explain how the electron distance from the nucleus relates to the amount of energy within that electron shell. Look at figure 9-3 for clarification.
The farther an electron's distance is from the nucleus, the more energy an atom has within its electron shell. Since they have higher energies, electrons are more able to "run off" or become farther from the nucleus.
(Mike)
More Distance = More Energy Less Distance = Less Energy
(Mike)
7. Which electrons – the most energetic electrons - determines interactions between atoms?
The valence electrons, which are the most energetic electrons, determines interactions between atoms.
8. Define the following terms: (Julie Le)
9. What is the difference between a structural and molecular formula? (Noreen Delfin)
A molecular formula shows the number of atoms in each molecule. A structural formula not only shows the amount of atoms in a molecule, but it also shows the arrangement of atoms as well.
This can be seen in the folllowing formulas for water:
The molecular formula for water is H2O.
The 2 in "H2O" refers to the number of Hydrogen atoms in one molecule of water. In this formula, oxygen has only one atom. The biggest difference between the molecular formula and the structural formula of water is the absence of the arrangement of atoms. From the formula H2O, we only know that there are two atoms of hydrogen and one atom of oxygen, but the formula does not tell us where they are located on the molecule. However, the arrangement can be seen in the structural formula.
The structural formula of water:
As seen in the above picture of the structural formula, we can see where the two hydrogens and one oxygen is arranged in the molecule. Essentially, this formula provides the number of atoms along with the structure of the atoms.
In the above picture of
10. How do ionic bonds compare with covalent bonds? (Compare Figures 2-7 and 2-9)
this is a ionic bond. This occurs when one ion has more electromagnetically then the other. One ion usual gives one or more valence electron to the other which allows the other ion to finish there outter shell.
this is a covalent bond. This occurs when atoms bond together and share one more more electrons. The electrons are shared and circle between both atoms that are bonded together.
The most distinguish difference from ionic and covalent is that ionic is more of giving an electron while covalent is a sharing of an electron.
Navy Swag
11. Compare and contrast hydrogen bonds and van der Waals interactions.
This is a hydrogen bond:
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom such as fluorine, oxygen, and nitrogen that comes from another molecule or chemical group. The hydrogen must be covalently bonded to another electronegative atom to create the bond.
On the other hand, this is Van der Waals Force
is an attractive force between atoms or nonpolar molecules caused by an instantaneous dipole moment of one atom or molecule that induces a similar temporary dipole moment in adjacent atoms or molecules.Although both are relatively weak, the hydrogen bond is stronger than Van der Waals' interactions
Debbie Trieu